The“glucose-bleached”and“etiolated”cells ofChlorella protothecoideshaving plastids of different degrees of degeneration were prepared by the methods previously reported, and the effects of actinomycin (C complex) upon the processes of greening of these cells were investigated under various experimental conditions. As has been shown previously, these cells formed normal chloroplasts on being incubated in the light with provision of nitrogen source (urea), but without glucose. The greening process of the glucose-bleached cells has been found to differ from that of the etiolated cells in the point that it involves a light-independent phase preceding a light-requiring phase. It was revealed that the greening of glucose-bleached cells is inhibited by actinomycin much more strongly than that of etiolated cells. On applying the antibiotic at different times during the chloroplast development in glucose-bleached cells, it was found that the inhibitory effect was remarkably reduced with the progress of the developmental process. This indicated that the antibiotic attacked more strongly the light-independent phase than the light-requiring phase in question. Based on these observations it was inferred that, in the process of chloroplast development in glucose-bleached cells, DNA and RNA are playing important roles, especially during the early light-independent phase of chloroplast deve
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